Along an assembly line, various types of articles, such as for example, diapers and other absorbent articles, may be assembled by adding components to and otherwise modifying and advancing, continuous webs of material. For example, in some processes, advancing webs of material are combined with other advancing webs of material. In other examples, individual components created from advancing webs of material are combined with advancing webs of material, which in turn, are then combined with other advancing webs of material. Webs of material and component parts used to manufacture diapers may include: backsheets, top sheets, absorbent cores, front and/or back ears, fastener components, and various types of elastic webs and components such as leg elastics, barrier leg cuff elastics, and waist elastics. Once the desired component parts are assembled, the advancing web(s) and component parts are subjected to a final knife cut to separate the web(s) into discrete diapers or other absorbent articles. The discrete diapers or absorbent articles may also then be folded and packaged.
Various methods and apparatuses may be used for attaching different components to an advancing web. Some production operations are configured to advance substrates in a machine direction at a constant speed. However, when advancing webs have components added thereto or are otherwise subjected to processing operations during production, it may be necessary to slow or stop the advancing web. For example, it may be necessary to slow or stop an advancing web passing through a processing station configured to perform such operations as, for example, gluing, welding, and adding discrete components. In an attempt to avoid having to vary the speed of the entire length of a substrate passing through an assembly line, some devices can be used to vary the speed of a portion of the substrate without affecting the speed of the entire substrate. However, such devices may only be configured to slow or stop the portion of the advancing web passing through a processing station for an instant or a very short duration of time, such as the time to process one single product. In turn, the processing stations may not be able to complete their respective functions during the relatively short time period while the web is slowed or stopped.
Other attempts have been made to process an advancing web such that the overall manufacturing line speed is not affected. For example, devices that shuttle the processing equipment at the speed of the web during processing and index the shuttle back to again process with the speed of the web have been developed. Due to the shuttling, which includes abrupt directional changes both horizontally and vertically, these devices are limited to smaller sizes and lighter weights. Further, these devices are limited as to how fast they can be shuttled; transferring a device at a high speed with high mass is difficult to control.
Still further, as the demand for consumer products increase, manufacturers are faced with having to produce products faster or at higher manufacturing throughput speeds. Thus, equipment is being developed which requires greater web handling capability. Accordingly, a need exists for a device that can suspend a portion of an advancing web for a predetermined dwell time, thereby keeping the web stationary for a time period longer than required to process a single product. For example, an apparatus is needed to stop a constantly advancing web at a gluing station so that three products can be glued and subsequently transported such that the line speed downstream of the apparatus is maintained. As previously stated, various methods and apparatuses have been developed to handle changing the web speed such that a fast operation, such as gluing or welding, that takes substantially less time than the period of one product, can be performed on one or more products. However, the current apparatuses are unable to handle a web such that one or more processes can be performed on the web over a time period greater than the time it takes to discharge one product from the complete manufacturing process. Stated another way, the current apparatuses are unable to handle processing a web for longer than the time allotted to move one product through the apparatus to maintain the desired line-speed downstream of the apparatus. Thus, a need exists for a device to handle the web such that more than one process can be performed on the web such that two or more products are processed simultaneously at zero speed for a time period longer than the time period required to process one product without affecting the overall speed of the web in subsequent manufacturing operations.